Metal door frame

ABSTRACT

This invention relates to metal door frames and is concerned with the problem of simplifying the manufacture of such door frames and, therefore, rendering them less costly to produce. According to the invention metal door jambs and wing frames are constructed in the form of special hollow profiles capable of being combined with one another to form boxlike posts so that many different kinds of metal doors can be manufactured using a relatively small number of profiles. In each case a jamb profile and a wing profile has a groove on the sides facing away from each other and, on their adjacent sides, other grooves the width of which increases with the depth of the grooves, which other grooves receive draught excluding sealing strips.

United States Patent 1 Wenig METAL DOOR FRAME [76] Inventor: Hans Wenig, Mullerstrasse 2, 58

Hagen/Westphalia, Germany [22] Filed: Aug. 13, 1970 [21] Appl. No.: 63,551

[30] Foreign Application Priority Data Aug. 16, 1969 Switzerland ..12574/69 [56] References Cited FOREIGN PATENTS OR APPLICATIONS 1,135,730 12/1968 Great Britain ..52/731 454,414 6/1968 Switzerland... ....52/73l 6,407,024 1/1965 Netherlands ..52/73l 51 May l, 1973 Primary ExaminerJ. Karl Bell Att0rney--Michael S. Striker [57] ABSTRACT This invention relates to metal door frames and is concerned with the problem of simplifying the manufacture of such door frames and, therefore, rendering them less costly to produce. According to the invention metal door jambs and wing frames are constructed in the form of special hollow profiles capable of being combined with one another to form boxlike posts so that many different kinds of metal doors can be manufactured using a relatively small number of profiles. In each case ajamb profile and a wing profile has a groove on the sides facing away from each other and, on their adjacent sides, other grooves the width of which increases with the depth of the grooves, which other grooves receive draught excluding sealing strips. 1

16 Claims, 4 Drawing Figures Patented May 1, 1973 2 Sheets-Sheet 2 lllllllidllillllflllll Fig4 METAL noon FRAME BACKGROUND OF THE INVENTION Metal door frames are being used in increasing measure in modern architecture, but their high price resulting from precise methods of execution still causes their application to be rather limited.

The object of the present invention is to simplify and at the same time render less costly the manufacture of metal door frames by using novel profiles, or sections,

constructed and specially suitable for this purpose,

which can be combined with one another.

The invention is based-on the consideration that, by the choice of specially constructed profiles capable of being combined with one another, numerous different kinds of metal doors can be manufactured using a relatively small number of profiles, thus resulting also in a simplification of storekeeping.

Consequently, a metal door frame according to the invention is constructed in such a way that it consists of a boxlike, substantially rectangular post having on one side a groove of rectangular cross-section, on the opposite side a protruding rib bordered on one side by a groove the width of which increases with its depth, and having a protruding bar on the side of the groove facing away from the rib.

It is useful for a boxlike post consisting of a combined first and second profile to have a first closed L- shaped profile closed by a standing rail protruding from the inside of a first side piece and running parallel to the inside of a second side piece, and an open sided second profile assembled onto the first profile. According to a further feature of the invention the rim of the second profile reinforced by folding through 180 is supported in the space between the standing rail of the first side piece and the inner side of the second side piece by bearing against the first profile, and this second profile has a flank running parallel to the inside of the first side piece, then a flank bent through 90 and level with the front side of the second side piece, then a flank lying adjacent to the outer side of the second side piece, a broad rib formed by repeated bending, and finally a groove formed by repeated bending which is bordered by the end of the profile folded through 180 and arranged in such a way that the groove increases in the direction of its depth.

In some cases it is advantageous for the boxlike post consisting of a first and a second profile to have a first, closed, profile substantially L-shaped which, on the side opposite the side provided with a groove, has a shallow recess of greater breadth than the groove and closed within the area of said recess by a lap joint, and a second, closed, profile, inserted into the shallow recess and closed by a standing rail having immediately adjacent to it a groove the breadth of which has adjacent thereto a broad, protruding shallow rib.

In a preferred embodiment the metal door frame consists of a first profile of substantially hammerlike shape closed by a standing railprotruding from a flank of the profile, and an open second profile assembled onto the first profile, the rim of which, reinforced by folding through 180, is supported in the space between the standing rail and the adjacent flank of the first profile by bearing against the latter, further having a flank which runs parallel to the flank of the first profile and from which the standing rail protrudes, then a flank bent through 90 and level with the front of the first profile, then a bent flank lying adjacent to the outside of the first profile, then a flank bent through 90, and finally, a flank running parallel to.the latter but offset, which runs adjacent to the outer side of the first profile and the end of which is supported by a protruding part of the first profile. According to a further feature of this embodiment there is provided a third, closed, profile which is inserted into a recess situated between the protruding part of the first and the protruding part of the second profile which is closed. by a standing rail immediately adjacent to which there is a groove the breadth of which increases in the direction of its depth and which has adjacent to it a broad protruding shallow rib.

Generally speaking it is advantageous if the blind or jamb frame as well as the wing frame consist of a boxlike profile according to the invention, if the boxlike profiles forming the jamb frame and the wing frame have the same outline, and if the outer walls and the inner walls of the jamb frame and the wing frame are level with each other.

For the purpose of excluding draughts, according to a further feature of the invention, an elastic strip is inserted into each of the parallel but laterally oppositely transposed grooves provided in the two sides of the jamb frame and the wing frame facing each other, and

the arrangement is such that, when the door is closed,

the part of the strip protruding from the groove comes into resilient contact with a protuberance on the opposite profile. It has been found useful to provide the elastic. strips in the form of synthetic tubes having a protruding hump preferably of dovetail shape inserted into the matching groove.

Naturally, it will be appreciated that many variations may be effected without departing from the spirit and scope of the present inventive concept.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing in which corresponding parts have been given the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a horizontal section of the profile of a jamb frame, and guided to lie adjacent to it, a wing frame composed of two profiles;

FIG. 2 is a horizontal section of another practical example of ajamb frame composed of two profiles, and of a wing frame composed oflike profiles;

FIG. 3 is a horizontal section of another practical example ofajamb frame composed of three profiles;

FIG. 4 is a horizontal section of a variant of the wing frame shown in FIG. 2 and composed of three profiles.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The arrangement illustrated in FIG. 1 shows a jamb frame 1 and, connected thereto by links not shown, a wing frame 3 pivoted about an axis 2. The jamb frame consists of a boxlike profile 4 having a substantially rectangular crossesection, the side of which facing the wall having a groove 5 of rectangular cross-section. On the side of the post facing the wing frame the post has a protruding shallow rib 6 bordered on one side by a groove 7 the width of which increases in the direction of its depth. On the side of the groove 7 facing away from the rib 6 the boxlike profile is closed by a standing rail 9 forming a protruding bar. The wing frame 3 is formed by a post consisting of a first closed profile 10 and a second open profile 11.

The profile 10 is substantially L-shaped and is closed by a standing rail 12 protruding from the inside of a side piece 13. The second profile has arim 14 reinforced by folding through l80, and disposed in the space between the standing rail 12 of the first side piece 13 and the inner side of a second rail 15, the rim 14 being held in position by hearing against the first profile 10. Further, the second profile 11 has a flank 16 running parallel to the inside of the first side piece 13, a flank 17 bent through 90 and level with the front side of the first side piece 13, a bent flank 19 adjacent to the front side of the second side piece, a broad rib 20 formed by repeated bending and constituting elongated engaging means, and finally a groove 21 formed by repeated bending bordered by the end of the profile folded through 180 thus forming a bar 22. An elastic strip 23 is inserted into each of the two parallel but oppositely transposed grooves 7 and 21. The strip consists of a tube of synthetic material having a protruding hump with a dove-tail shaped cross-section, which is inserted into the matching groove. These synthetic tubes or sealing members 23, which serve to provide airtightness, are arranged in mirror image one to the other, and, when the door is closed, form a chamber which prevents any draughts. The pivotal axis 2 is positioned in the space between the two inner sides of the jamb frame 1 and the wing frame 3 facing each other, in the immediate vicinity of one of the two bars 9 and 22 respectively supporting the synthetic tubes from the outside.

The standing rail 12 and the rim 14 of the second profile, held in position by bearing against it and reinforced by folding over, result, in combination, in an effective rigidity of the composite boxlike post which is advantageous for wide doors. Line 24 indicates where the composite post may be screwed together; the standing rail 22 covers the screws.

The outer profiles of the jamb frame 31 illustrated in FIG. 2 and of the wing frame 32 are identical with those ofjamb frame 1 and wing frame 3 in FIG. 1; however, the protruding broad shallow rib 6 illustrated in FIG. 1 is formed in the jamb frame 31 as well as in the wing frame 32 by an inserted part. Jamb frame 31 and wing frame 32 are arranged in the same way but in mirror image one to the other. Both consist of a first closed profile 33, each having on the sides facing away from each other a groove 5 and on the sides facing each other a shallow recess which is considerably broader than the said groove 5. In the area of this recess each profile is closed by a lap joint 34. A profile 35, which is closed by a standing rail 36, is inserted into each of the two broad shallow recesses. Immediately adjacent to each standing rail 36 there is a groove the breadth of which increases in the direction of its depth and into which an elastic strip 23 is inserted. This strip is made in the same way, and its functions are the same as those already described in connection with FIG. 1. Each profile 35 has a broad protruding shallow rib 37 immediately adjacent to the groove filled with strip 23.

Again, in the embodiment according to FIG. 3, the outer outline of the profiles used therein corresponds substantially with that of the embodiment according to FIG. 1. Analoguous boxlike posts are used for jamb frame 41 and for wing frame 42, and these consist of assembled profiles. The profile 43 which is of first importance in the construction of the post has a hammerlike shape and is closed by a standing rail 44. Fitted onto this profile 43 is an open profile 45 whose rim 46 is reinforced by folding over and which supports itself in the space between the standing rail 44 and the adjacent flank 47 of the first profile 43 by bearing against the latter. The second profile 45 has, furthermore, a flank 48 running parallel to the flank of the first profile 41 which the standing rail 44 protrudes. This is continued by flank 49 bent at and level with one of the flanks of the first profile, followed by a bent flank 50 lying adjacent to the outside of the first profile. In continuation of the next flank 51 angled by 90 there follows a flank 52 running parallel but offset with regard to flank 51 and which lies adjacent to an outer side of the first profile. The end of flank 51 is folded through and is supported by a protruding part of the first profile. A third closed profile 54 is inserted into each of the shallow recesses formed by parts of the first and second profiles. The arrangement of profile 54 and its functions are identical to those of profile 35 of FIG. 2, and the same applies to the shape and function of the inserted elastic strips 23. i

A further embodiment of the invention is shown in FIG. 4. The jamb frame 31 is arranged in the same way as the jamb frame 31 of FIG. 2, whereas the arrangement of the wing frame 61 corresponds with that of the wing frame 42 of FIG. 3. Wing frames 42 and 61 differ only in their relationships between breadth and depth. In the variants of the wing frames illustrated in FIGS. 3 and 4, the assembly is made easier in that, when assembling the larger closed and the smaller open profiles, the standing rail 44 forms a good lead-in for the rim 46 which is reinforced by folding over.

The sides of the metal facing each other inside the rails are roughened, preferably by interlocking notches, in order to safeguard these parts against a relative lengthwise dislodgement.

The invention has been described above in its application to doors that open to one side (so-called pushdoors). However, it is possible to modify the metal door frame in such a way that it will be suitable for doors opening to either side (so-called swing-doors). For this purpose it will suffice to replace both the inserts between the jamb frame and the wing frame inserted into recesses and facing each other and consisting substantially of profile 35, by a different insert which, on the sides facing each other, has the shape of a ball. These two inserts have each a groove facing each other, into which an elastic strip is inserted. In both arrangements, therefore, the elastic airtight strips inserted into the corresponding grooves ensure the exclusion of draughts.

The profiles according to the present invention may be manufactured by cold rolling and the process may be continuous. Any suitable materials may beused, preferably non-corroding, such as non-rusting high quality steel.

Many possible modifications will become apparent from the foregoing without departing from the spirit of the present invention. However, the foregoing disclosure is presented in an illustrative sense rather than a limiting sense and the appended claims are relied upon to define the scope of the present invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

l. A closure arrangement comprising, in combination, a stationary elongated frame member having an elongated inner side; a movable closure member including a movable elongated frame member also having an elongated inner side; mounting means for mounting said movable closure member with said movable elongated frame member pivotably movable about an axis parallel to the elongation of said frame members and arranged in a plane intermediate said frame members and in direction substantially normal to said inner side of said movable frame member between a closing position wherein said inner sides of said frame members are substantially adjacent and an open position wherein said inner sides are substantially spaced; an elongated at least substantially dovetail-shaped groove located in the inner side of at least one of said elongated frame members facing the inner side of the other one of said elongated frame members when said movable closure member having an elongated holding portion located and held within said elongated dovetailshaped groove and having an elongated sealing portion located outside said elongated dovetailshaped groove; and elongated engaging means, provided on said other elongated frame member and positioned opposite said sealing member when said closure member is in said closing position thereof, and operative for pressing against said elongated sealing portion in direction substantially normal to said inner side of said movable frame member when said closure member is in said closing position thereof.

2. A closure arrangement as defined in claim 1, wherein said one of said frame members is an elongated hollow profiled member of generally rectangular crosssectional configuration having a side opposite said elongated inner side provided with an elongated groove of generally rectangular cross-sectional outline.

3. A closure arrangement as defined in claim 1, wherein said frame members are elongated hollow profiled members having substantially the same crosssectional configuration.

4. A closure arrangement as defined in claim I, wherein said one frame member is further provided on its inner side with an elongated projecting rib flanking and at least in part bounded by said elongated dovetailshaped groove.

5. A closure arrangement as defined in claim 1, wherein said one frame member is a hollow profiled member of folded sheet metal.

6. A closure arrangement as defined in claim 1, wherein said one frame member is a hollow profiled member whose cross-sectional configuration is defined by a single piece of folded sheet metal.

7. A closure arrangement as defined in claim 1, wherein said one frame member is a hollow profiled member whose crosssectional configuration is defined by a plurality of pieces of folded sheet metal.

8.'A closure arrangement as defined in claim 1, wherein each of said inner sides is provided with an elongated at least substantially dovetail-shaped groove, and wherein each of said grooves receives and retains an elongated holding portion of an elongated sealing member, and wherein each of said frame members is provided with elongated engaging means.

9. A closure arrangement as defined in claim 1, wherein said elongated sealing member comprises an elongated elastic strip.

10. A closure arrangement as. defined in claim 1,

. wherein said elongated sealing member comprises an elongated elastic tube.

11. A closure arrangement as defined in claim 1, wherein said holding portion of said sealing member is of generally dovetail-shaped cross-sectional configuratron.

12. A closure arrangement as defined in claim 1, wherein at least said other of said frame members comprises a first closed profile and a second open profile assembled toform a box-like post having a first groove extending lengthwise of said post, said second profile having an elongated longitudinally extending rim folded over upon itself by said first profile having a longitudinally extending joint in the form of an elongated protruding standing rail and a first elongated flank normal to said rail and a second elongated flank adjacent to said first flank and parallel to the direction of protrusion of said rail, said rim being supported in a space between said standing rail and said second flank, and said other of said frame members having a protruding rib on the side thereof facing said one of said frame members, said rib forming one side of said dovetailshaped groove and further including a standing fold forming another side of said dovetail-shaped groove. 7

13. A closure arrangement as defined in claim I, wherein said one of said frame members comprises a first closed profile and a second closed profile assembled to form a box-like post, said first closed profile being four-sided and substantially rectangular and having on one side a reentrant groove of predetermined breadth and depth extending lengthwise of said post and having on the side opposite said one side a shallow recess of greater breadth than said groove, a lap-joint forming part of said shallow recess and serving to close said first profile, and wherein said second profile is received in said shallow recess, said second profile having a longitudinal standing rail serving to close said second profile and forming one side of said dovetailshaped groove and further including a broad protruding shallow rib forming the other side of said dovetailshaped groove.

14. A closure arrangement as defined in claim 1, wherein one of said frame members comprises a first closed profile, a second open profile and a third .closed profile assembled together to form a box-like post, said first and second profiles each having a plurality of flanks and said first and third profiles each being closed by a standing rail, said open profile having a rim and having at least two sides of said rim reinforced by folding through 180, said first profile being of substantially hammerlike shape, said standing rail of said first profile protruding from a first flank of said first profile and extending parallel to a second and adjacent flank of said first profile, one reinforced side of said'second profile being supported ina space between said standing rail of said first profile and said second flank of said first profile by bearing against the latter, said second profile having a first flank running parallel to said first flank of said first profile, a second flank bent through 90 and running parallel to said second flank of said first profile, then a third flank adjoining a third and outer flank of said first profile, then a fourth flank bent through 90, and finally a fifth flank, forming the other of said reinforcing sides, running parallel to the latter but offset so that it forms a recess and adjoins a fourth and outer flank of said first profile, the end of said other reinforced side bearing thereagainst and being supported thereby, said third profile being received in said recess, said standing rail forming one side of said dovetail-shaped groove, and said third profile having a broad protruding shallow rib forming the other side of said groove.

15. A closure arrangement as defined in claim 1, wherein said one of said frame members comprises a first, closed, profile and a second, open, profile assembled thereon to provide a box-like post, said first profile being L-shaped and being closed by a standing rail protruding from the inside of a first side piece and running parallel to the inside of a second side piece said second profile having a rim and having at least one side of said rim reinforced by folding through 180 and, when assembled on said first profile, said one side being supported in a space between said standing rail and said second side piece of said first profile by bearing against the latter, said second profile further having a first flank running parallel to the inside of said first side piece of said first profile, followed by a second flank which is bent through and level with a front side of said first side piece of said first profile, followed by a third flank bent through 90 so as to lie adjacent a front side of said second side piece of said first profile, then by a fourth flank lying adjacent to an outer side of said aforementioned second side piece, followed by a broad rib bounding said dovetail-shaped groove.

16. A closure arrangement as defined in claim 1, wherein said one of said frame members comprises a first closed profile and a second closed profile assembled to provide a box-like post, said first closed profile being four-sided and substantially rectangular and having on one side a reentrant groove of predetermined breadth and depth extending lengthwise of the post and having on the side opposite said one side a shallow recess of greater breadth than said groove, a lap-joint forming part of said shallow recess, and serving to close said first profile; wherein said second profile is inserted into said shallow recess, said second profile having a longitudinal standing rail serving to close said second profile and located to one side of said dovetail-shaped groove, and a broad protruding shallow rib located to the other side of said dovetail-shaped groove. 

1. A closure arrangement comprising, in combination, a stationary elongated frame member having an elongated inner side; a movable closure member including a movable elongated frame member also having an elongated inner side; mounting means for mounting said movable closure member with said movable elongated frame member pivotably movable about an axis parallel to the elongation of said frame members and arranged in a plane intermediate said frame members and in direction substantially normal to said inner side of said movable frame member between a closing position wherein said inner sIdes of said frame members are substantially adjacent and an open position wherein said inner sides are substantially spaced; an elongated at least substantially dovetail-shaped groove located in the inner side of at least one of said elongated frame members facing the inner side of the other one of said elongated frame members when said movable closure member having an elongated holding portion located and held within said elongated dovetail-shaped groove and having an elongated sealing portion located outside said elongated dovetail-shaped groove; and elongated engaging means, provided on said other elongated frame member and positioned opposite said sealing member when said closure member is in said closing position thereof, and operative for pressing against said elongated sealing portion in direction substantially normal to said inner side of said movable frame member when said closure member is in said closing position thereof.
 2. A closure arrangement as defined in claim 1, wherein said one of said frame members is an elongated hollow profiled member of generally rectangular cross-sectional configuration having a side opposite said elongated inner side provided with an elongated groove of generally rectangular cross-sectional outline.
 3. A closure arrangement as defined in claim 1, wherein said frame members are elongated hollow profiled members having substantially the same cross-sectional configuration.
 4. A closure arrangement as defined in claim 1, wherein said one frame member is further provided on its inner side with an elongated projecting rib flanking and at least in part bounded by said elongated dovetail-shaped groove.
 5. A closure arrangement as defined in claim 1, wherein said one frame member is a hollow profiled member of folded sheet metal.
 6. A closure arrangement as defined in claim 1, wherein said one frame member is a hollow profiled member whose cross-sectional configuration is defined by a single piece of folded sheet metal.
 7. A closure arrangement as defined in claim 1, wherein said one frame member is a hollow profiled member whose cross-sectional configuration is defined by a plurality of pieces of folded sheet metal.
 8. A closure arrangement as defined in claim 1, wherein each of said inner sides is provided with an elongated at least substantially dovetail-shaped groove, and wherein each of said grooves receives and retains an elongated holding portion of an elongated sealing member, and wherein each of said frame members is provided with elongated engaging means.
 9. A closure arrangement as defined in claim 1, wherein said elongated sealing member comprises an elongated elastic strip.
 10. A closure arrangement as defined in claim 1, wherein said elongated sealing member comprises an elongated elastic tube.
 11. A closure arrangement as defined in claim 1, wherein said holding portion of said sealing member is of generally dovetail-shaped cross-sectional configuration.
 12. A closure arrangement as defined in claim 1, wherein at least said other of said frame members comprises a first closed profile and a second open profile assembled to form a box-like post having a first groove extending lengthwise of said post, said second profile having an elongated longitudinally extending rim folded over upon itself by 180*, said first profile having a longitudinally extending joint in the form of an elongated protruding standing rail and a first elongated flank normal to said rail and a second elongated flank adjacent to said first flank and parallel to the direction of protrusion of said rail, said rim being supported in a space between said standing rail and said second flank, and said other of said frame members having a protruding rib on the side thereof facing said one of said frame members, said rib forming one side of said dovetail-shaped groove and further including a standing fold forming another side of said dovetail-shaped groove.
 13. A closure arrangement as defined in claim 1, wherein saiD one of said frame members comprises a first closed profile and a second closed profile assembled to form a box-like post, said first closed profile being four-sided and substantially rectangular and having on one side a reentrant groove of predetermined breadth and depth extending lengthwise of said post and having on the side opposite said one side a shallow recess of greater breadth than said groove, a lap-joint forming part of said shallow recess and serving to close said first profile, and wherein said second profile is received in said shallow recess, said second profile having a longitudinal standing rail serving to close said second profile and forming one side of said dovetail-shaped groove and further including a broad protruding shallow rib forming the other side of said dovetail-shaped groove.
 14. A closure arrangement as defined in claim 1, wherein one of said frame members comprises a first closed profile, a second open profile and a third closed profile assembled together to form a box-like post, said first and second profiles each having a plurality of flanks and said first and third profiles each being closed by a standing rail, said open profile having a rim and having at least two sides of said rim reinforced by folding through 180*, said first profile being of substantially hammerlike shape, said standing rail of said first profile protruding from a first flank of said first profile and extending parallel to a second and adjacent flank of said first profile, one reinforced side of said second profile being supported in a space between said standing rail of said first profile and said second flank of said first profile by bearing against the latter, said second profile having a first flank running parallel to said first flank of said first profile, a second flank bent through 90* and running parallel to said second flank of said first profile, then a third flank adjoining a third and outer flank of said first profile, then a fourth flank bent through 90*, and finally a fifth flank, forming the other of said reinforcing sides, running parallel to the latter but offset so that it forms a recess and adjoins a fourth and outer flank of said first profile, the end of said other reinforced side bearing thereagainst and being supported thereby, said third profile being received in said recess, said standing rail forming one side of said dovetail-shaped groove, and said third profile having a broad protruding shallow rib forming the other side of said groove.
 15. A closure arrangement as defined in claim 1, wherein said one of said frame members comprises a first, closed, profile and a second, open, profile assembled thereon to provide a box-like post, said first profile being L-shaped and being closed by a standing rail protruding from the inside of a first side piece and running parallel to the inside of a second side piece said second profile having a rim and having at least one side of said rim reinforced by folding through 180* and, when assembled on said first profile, said one side being supported in a space between said standing rail and said second side piece of said first profile by bearing against the latter, said second profile further having a first flank running parallel to the inside of said first side piece of said first profile, followed by a second flank which is bent through 90* and level with a front side of said first side piece of said first profile, followed by a third flank bent through 90* so as to lie adjacent a front side of said second side piece of said first profile, then by a fourth flank lying adjacent to an outer side of said aforementioned second side piece, followed by a broad rib bounding said dovetail-shaped groove.
 16. A closure arrangement as defined in claim 1, wherein said one of said frame members comprises a first closed profile and a second closed profile assembled to provide a box-like post, said first closed profile being four-sided and substantiAlly rectangular and having on one side a reentrant groove of predetermined breadth and depth extending lengthwise of the post and having on the side opposite said one side a shallow recess of greater breadth than said groove, a lap-joint forming part of said shallow recess, and serving to close said first profile; wherein said second profile is inserted into said shallow recess, said second profile having a longitudinal standing rail serving to close said second profile and located to one side of said dovetail-shaped groove, and a broad protruding shallow rib located to the other side of said dovetail-shaped groove. 